A heavy particle hanging from fixed point by light inextensible string of length l is projected horizontally with speed $\sqrt {gl}$. Find speed of particle at the instant of the motion when tension in the string is equal to weight of particle

Question

$$(a)\;v=\sqrt {\frac{g}{3l}} \quad (b)\;v=\sqrt {\frac{gl}{3}} \quad (c)\;v=\frac{gl}{3}\quad (d)\;v= \frac{g}{3l}$$